Corrosion of mild steel in acidic environments is a chief industrial concern, leading to material degradation, economic losses, and reduced material life. The present study was undertaken to explore an ecofriendly and sustainable alternative to conventional toxic corrosion inhibitors. The corrosion inhibition performance of Phoenix dactylifera bark extract was evaluated on mild steel in 0.5 M nitric acid medium. The butanoic extract was prepared using the Soxhlet extraction method and its inhibitory action was assessed by the gravimetric weight loss method. Results showed that the extract significantly reduced the corrosion rate, with inhibition efficiency increasing at higher concentrations. The adsorption of phytochemical constituents followed the Langmuir adsorption isotherm, resulting in effective surface coverage and the formation of a protective film. These findings highlight the potential of P. dactylifera bark extract as a green, cost-effective, and environmentally benign corrosion inhibitor.